Kate, age 14, presents to you with her mother.  They are concerned because her periods are occurring less often, up to 6-7 weeks between periods.  Her last period was 6 weeks ago.  Her periods started around age 12, and were irregular for 6-12 months, then regular but in the last 6 months they are reducing.  She denies any period pain. 

She is quite active at school in various sports, her academic scores are very high and she is in the school debating team.  She is eating less and has lost weight because of bullying about over the last 6-9 months. She admits to “sometimes” vomiting after meals.  She has no other past medical history and no allergies.  Her BP is 90/50, HR 52 and she looks pale.  Her BMI is 18.

What are your differential diagnoses? List 5

1. Anorexia Nervosa [or eating disorder]
2. Excessive exercise induced hypothalamic amenorrhoea – IS THIS OVERCODING?
3. Stress induced hypothalamic amenorrhoea
4. Hyperthyroidism
5. Hyperprolactineamia from pituitary adenoma
6. PCOS

RACGP – Good answers in this case required giving the right number of important diagnoses to consider and not providing lists with examples or clarification.

What investigations will you perform?

1. Pregnancy test
2. Serum prolactin
3. Androgen studies
4. LH
5. FSH
6. TSH
7. FBE [for anaemia]
8. EUC [for electrolyte abnormalities if eating disorder/purging]
9. Pelvic USS
10. LFTs [for albumin] (1)
11. Iron studies  (1)
12. Bone density (1)

RACGP – Candidates identified the most important investigations to assess the differential diagnosis.

All investigations are normal except low-normal FSH and LH, her weight continues to reduce as she does not want to eat and sometimes vomits after meals, what is your management?

1. Give information that eating disorder is likely cause
2. Increase caloric intake
3. Reduce excessive exercise
4. Referral to adolescent psychiatrist for likely eating disorder
5. Referral to dietitian
6. Referral to adolescent psychologist for bullying support – IS THIS SAME MARKS AS Q4 and KIND OF THE SAME?
7. Regular monitoring for weight

RACGP – The management of the presentation, in light of normal results, and the information in the scenario pointed to the most likely diagnosis of an eating disorder.  Those candidates not scoring well focussed on non-specific answers such as referral, contraceptive advice, and using screening tools for unrelated issues or giving answers that covered the same conceptual areas.

RACGP Feedback

This case centred on the presentation of a 14 year old girl with her mother who is concerned that her daughter’s menstrual pattern has changed.  A differential diagnosis along with subsequent investigations is required and then the ongoing management of the patient in the light of normal results.

Good answers in this case required giving the right number of important diagnoses to consider and not providing lists with examples or clarification.  Candidates identified the most important investigations to assess the differential diagnosis.  The management of the presentation, in light of normal results, and the information in the scenario pointed to the most likely diagnosis of an eating disorder.  Those candidates not scoring well focussed on non-specific answers such as referral, contraceptive advice, and using screening tools for unrelated issues or giving answers that covered the same conceptual areas.

GPCC Feedback

This is an example of a broad question that requires multiple differentials, as opposed to the other type of commonly encountered question which will be of a specific disease with a narrow focus. Not all the questions require this level of clinical reasoning, but some do, and knowing how to answer them well still relies on having the building blocks of knowledge to sort through.  The main question is still “what are the causes of secondary amenorrhoea and weight loss” when you think about it.

The question would lead itself into other questions about adolescent health, the HEADSS screen. There are many good resources on adolescent health in all of the usual sources, and learning this topic is a specialty in itself, and one that is mostly unique to General Practice.